lib: support labelled nexthops in nexthop_groups

Add support for labelled nexthops in nexthop-group
vtysh configuration. Also update the PBR doc where
the cli is described.

Signed-off-by: Mark Stapp <mjs@voltanet.io>

doc/user/pbr.rst

@@ -39,7 +39,7 @@ listing of ECMP nexthops used to forward packets for when a pbr-map is matched.
    sub-mode where you can specify individual nexthops.  To exit this mode type
    exit or end as per normal conventions for leaving a sub-mode.
 
-.. clicmd:: nexthop [A.B.C.D|X:X::X:XX] [interface] [nexthop-vrf NAME]
+.. clicmd:: nexthop [A.B.C.D|X:X::X:XX] [interface] [nexthop-vrf NAME] [label LABELS]
 
    Create a v4 or v6 nexthop.  All normal rules for creating nexthops that you
    are used to are allowed here.  The syntax was intentionally kept the same as

lib/nexthop_group.c

@@ -34,6 +34,16 @@
 
 DEFINE_MTYPE_STATIC(LIB, NEXTHOP_GROUP, "Nexthop Group")
 
+/*
+ * Internal struct used to hold nhg config strings
+ */
+struct nexthop_hold {
+	char *nhvrf_name;
+	union sockunion *addr;
+	char *intf;
+	char *labels;
+};
+
 struct nexthop_group_hooks {
 	void (*new)(const char *name);
 	void (*add_nexthop)(const struct nexthop_group_cmd *nhg,
@@ -425,7 +435,11 @@ static int nhgl_cmp(struct nexthop_hold *nh1, struct nexthop_hold *nh2)
 	if (ret)
 		return ret;
 
-	return nhgc_cmp_helper(nh1->nhvrf_name, nh2->nhvrf_name);
+	ret = nhgc_cmp_helper(nh1->nhvrf_name, nh2->nhvrf_name);
+	if (ret)
+		return ret;
+
+	return nhgc_cmp_helper(nh1->labels, nh2->labels);
 }
 
 static void nhgl_delete(struct nexthop_hold *nh)
@@ -437,6 +451,8 @@ static void nhgl_delete(struct nexthop_hold *nh)
 	if (nh->addr)
 		sockunion_free(nh->addr);
 
+	XFREE(MTYPE_TMP, nh->labels);
+
 	XFREE(MTYPE_TMP, nh);
 }
 
@@ -510,7 +526,8 @@ DEFUN_NOSH(no_nexthop_group, no_nexthop_group_cmd, "no nexthop-group NHGNAME",
 static void nexthop_group_save_nhop(struct nexthop_group_cmd *nhgc,
 				    const char *nhvrf_name,
 				    const union sockunion *addr,
-				    const char *intf)
+				    const char *intf,
+				    const char *labels)
 {
 	struct nexthop_hold *nh;
 
@@ -522,6 +539,8 @@ static void nexthop_group_save_nhop(struct nexthop_group_cmd *nhgc,
 		nh->intf = XSTRDUP(MTYPE_TMP, intf);
 	if (addr)
 		nh->addr = sockunion_dup(addr);
+	if (labels)
+		nh->labels = XSTRDUP(MTYPE_TMP, labels);
 
 	listnode_add_sort(nhgc->nhg_list, nh);
 }
@@ -529,7 +548,8 @@ static void nexthop_group_save_nhop(struct nexthop_group_cmd *nhgc,
 static void nexthop_group_unsave_nhop(struct nexthop_group_cmd *nhgc,
 				      const char *nhvrf_name,
 				      const union sockunion *addr,
-				      const char *intf)
+				      const char *intf,
+				      const char *labels)
 {
 	struct nexthop_hold *nh;
 	struct listnode *node;
@@ -537,7 +557,8 @@ static void nexthop_group_unsave_nhop(struct nexthop_group_cmd *nhgc,
 	for (ALL_LIST_ELEMENTS_RO(nhgc->nhg_list, node, nh)) {
 		if (nhgc_cmp_helper(nhvrf_name, nh->nhvrf_name) == 0 &&
 		    nhgc_addr_cmp_helper(addr, nh->addr) == 0 &&
-		    nhgc_cmp_helper(intf, nh->intf) == 0)
+		    nhgc_cmp_helper(intf, nh->intf) == 0 &&
+		    nhgc_cmp_helper(labels, nh->labels) == 0)
 			break;
 	}
 
@@ -551,10 +572,19 @@ static void nexthop_group_unsave_nhop(struct nexthop_group_cmd *nhgc,
 	nhgl_delete(nh);
 }
 
+/*
+ * Parse the config strings we support for a single nexthop. This gets used
+ * in a couple of different ways, and we distinguish between transient
+ * failures - such as a still-unprocessed interface - and fatal errors
+ * from label-string parsing.
+ */
 static bool nexthop_group_parse_nexthop(struct nexthop *nhop,
 					const union sockunion *addr,
-					const char *intf, const char *name)
+					const char *intf, const char *name,
+					const char *labels,
+					int *lbl_ret)
 {
+	int ret = 0;
 	struct vrf *vrf;
 
 	memset(nhop, 0, sizeof(*nhop));
@@ -592,16 +622,49 @@ static bool nexthop_group_parse_nexthop(struct nexthop *nhop,
 	} else
 		nhop->type = NEXTHOP_TYPE_IFINDEX;
 
+	if (labels) {
+		uint8_t num = 0;
+		mpls_label_t larray[MPLS_MAX_LABELS];
+
+		ret = mpls_str2label(labels, &num, larray);
+
+		/* Return label parse result */
+		if (lbl_ret)
+			*lbl_ret = ret;
+
+		if (ret < 0)
+			return false;
+		else if (num > 0)
+			nexthop_add_labels(nhop, ZEBRA_LSP_NONE,
+					   num, larray);
+	}
+
 	return true;
 }
 
+/*
+ * Wrapper to parse the strings in a 'nexthop_hold'
+ */
+static bool nexthop_group_parse_nhh(struct nexthop *nhop,
+				    const struct nexthop_hold *nhh)
+{
+	return (nexthop_group_parse_nexthop(nhop, nhh->addr,
+					    nhh->intf,
+					    nhh->nhvrf_name,
+					    nhh->labels,
+					    NULL));
+}
+
 DEFPY(ecmp_nexthops, ecmp_nexthops_cmd,
       "[no] nexthop\
         <\
 	  <A.B.C.D|X:X::X:X>$addr [INTERFACE$intf]\
 	  |INTERFACE$intf\
 	>\
-	[nexthop-vrf NAME$vrf_name]",
+	[{ \
+	   nexthop-vrf NAME$vrf_name \
+	   |label WORD \
+	}]",
       NO_STR
       "Specify one of the nexthops in this ECMP group\n"
       "v4 Address\n"
@@ -609,14 +672,18 @@ DEFPY(ecmp_nexthops, ecmp_nexthops_cmd,
       "Interface to use\n"
       "Interface to use\n"
       "If the nexthop is in a different vrf tell us\n"
-      "The nexthop-vrf Name\n")
+      "The nexthop-vrf Name\n"
+      "Specify label(s) for this nexthop\n"
+      "One or more labels in the range (16-1048575) separated by '/'\n")
 {
 	VTY_DECLVAR_CONTEXT(nexthop_group_cmd, nhgc);
 	struct nexthop nhop;
 	struct nexthop *nh;
+	int lbl_ret = 0;
 	bool legal;
 
-	legal = nexthop_group_parse_nexthop(&nhop, addr, intf, vrf_name);
+	legal = nexthop_group_parse_nexthop(&nhop, addr, intf, vrf_name,
+					    label, &lbl_ret);
 
 	if (nhop.type == NEXTHOP_TYPE_IPV6
 	    && IN6_IS_ADDR_LINKLOCAL(&nhop.gate.ipv6)) {
@@ -625,10 +692,31 @@ DEFPY(ecmp_nexthops, ecmp_nexthops_cmd,
 		return CMD_WARNING_CONFIG_FAILED;
 	}
 
+	/* Handle label-string errors */
+	if (!legal && lbl_ret < 0) {
+		switch (lbl_ret) {
+		case -1:
+			vty_out(vty, "%% Malformed label(s)\n");
+			break;
+		case -2:
+			vty_out(vty,
+				"%% Cannot use reserved label(s) (%d-%d)\n",
+				MPLS_LABEL_RESERVED_MIN,
+				MPLS_LABEL_RESERVED_MAX);
+			break;
+		case -3:
+			vty_out(vty,
+				"%% Too many labels. Enter %d or fewer\n",
+				MPLS_MAX_LABELS);
+			break;
+		}
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+
 	nh = nexthop_exists(&nhgc->nhg, &nhop);
 
 	if (no) {
-		nexthop_group_unsave_nhop(nhgc, vrf_name, addr, intf);
+		nexthop_group_unsave_nhop(nhgc, vrf_name, addr, intf, label);
 		if (nh) {
 			_nexthop_del(&nhgc->nhg, nh);
 
@@ -646,7 +734,7 @@ DEFPY(ecmp_nexthops, ecmp_nexthops_cmd,
 			_nexthop_add(&nhgc->nhg.nexthop, nh);
 		}
 
-		nexthop_group_save_nhop(nhgc, vrf_name, addr, intf);
+		nexthop_group_save_nhop(nhgc, vrf_name, addr, intf, label);
 
 		if (legal && nhg_hooks.add_nexthop)
 			nhg_hooks.add_nexthop(nhgc, nh);
@@ -696,6 +784,16 @@ void nexthop_group_write_nexthop(struct vty *vty, struct nexthop *nh)
 		vrf = vrf_lookup_by_id(nh->vrf_id);
 		vty_out(vty, " nexthop-vrf %s", vrf->name);
 	}
+
+	if (nh->nh_label && nh->nh_label->num_labels > 0) {
+		char buf[200];
+
+		mpls_label2str(nh->nh_label->num_labels,
+			       nh->nh_label->label,
+			       buf, sizeof(buf), 0);
+		vty_out(vty, " label %s", buf);
+	}
+
 	vty_out(vty, "\n");
 }
 
@@ -715,6 +813,9 @@ static void nexthop_group_write_nexthop_internal(struct vty *vty,
 	if (nh->nhvrf_name)
 		vty_out(vty, " nexthop-vrf %s", nh->nhvrf_name);
 
+	if (nh->labels)
+		vty_out(vty, " label %s", nh->labels);
+
 	vty_out(vty, "\n");
 }
 
@@ -751,9 +852,7 @@ void nexthop_group_enable_vrf(struct vrf *vrf)
 			struct nexthop nhop;
 			struct nexthop *nh;
 
-			if (!nexthop_group_parse_nexthop(&nhop, nhh->addr,
-							 nhh->intf,
-							 nhh->nhvrf_name))
+			if (!nexthop_group_parse_nhh(&nhop, nhh))
 				continue;
 
 			nh = nexthop_exists(&nhgc->nhg, &nhop);
@@ -787,9 +886,7 @@ void nexthop_group_disable_vrf(struct vrf *vrf)
 			struct nexthop nhop;
 			struct nexthop *nh;
 
-			if (!nexthop_group_parse_nexthop(&nhop, nhh->addr,
-							 nhh->intf,
-							 nhh->nhvrf_name))
+			if (!nexthop_group_parse_nhh(&nhop, nhh))
 				continue;
 
 			nh = nexthop_exists(&nhgc->nhg, &nhop);
@@ -824,9 +921,7 @@ void nexthop_group_interface_state_change(struct interface *ifp,
 			for (ALL_LIST_ELEMENTS_RO(nhgc->nhg_list, node, nhh)) {
 				struct nexthop nhop;
 
-				if (!nexthop_group_parse_nexthop(
-					    &nhop, nhh->addr, nhh->intf,
-					    nhh->nhvrf_name))
+				if (!nexthop_group_parse_nhh(&nhop, nhh))
 					continue;
 
 				switch (nhop.type) {

lib/nexthop_group.h

@@ -70,12 +70,6 @@ void nexthop_group_mark_duplicates(struct nexthop_group *nhg);
 	(nhop) = nexthop_next(nhop)
 
 
-struct nexthop_hold {
-	char *nhvrf_name;
-	union sockunion *addr;
-	char *intf;
-};
-
 struct nexthop_group_cmd {
 
 	RB_ENTRY(nexthop_group_cmd) nhgc_entry;